The present invention refers to a holding device for pick-up, transport and targeted deposit of small components.
There is a particular need for a holding device of this nature for the assembly of circuit boards--conductive boards--when the individual components are removed from a container with a great number of similar components and thereafter must be identified and located in a position and orientation on the board as determined by the wiring, whereafter they will be soldered to their connections.
Thereby, the deposit of various electrical components occurs in accordance with a precisely predetermined program whereby, if necessary, light point indicators or similar aids are provided.
Recently, miniature components, particularly SMD circuit elements, have become known, in the use of which the common manual work method is no longer possible, and which, contrary to earlier electrical components, are no longer provided with actual wire connections that extend from the component and accordingly can easily be soldered. These miniature components generally have end to end contact, and soldering of a component held between the fingers is thus excluded from the very beginning. The use of tweezers is very time-consuming, since the removal of individual components from a container generally does not allow the proper spatial allocation between holder (tweezer) and component.
A number of pick-up grippers or pipettes have already been suggested, which generally consist of a holding head with a holding shaft, whereby the individual components are suctioned up to a suction opening in the holding head via a suction line, transferred in this manner, and deposited on the circuit board.
The devices facilitate a simple pick-up of the individual components and generally also a faultless deposit of the component on a circuit board at the location desired in each case.
In some executions, the source of negative pressure, which is generally connected via a connecting hose through the gripper part to the holding head and its exit opening, is switched on and off by means of a pedal switch. Thereby, movements of hand and feet must be precisely coordinated, and since the deposit of a miniature component onto a circuit board requires extreme concentration, the operator is disturbed by the additional foot movement, which also easily causes a jarring movement, whereby the component might in some cases be dislocated precisely at that moment when it should be deposited, and consequently, it is incorrectly soldered.
Increase and decrease of negative pressure in this type of manual equipment are also too slow for many purposes.
Holding devices for the abovementioned components have also become known, in which the increase and decrease of pressure is initiated via a switch in the handle or an air escape opening which is opened and closed by the operator. This also causes the disadvantage that additional jarring movements may occur due to the activation of a switch in the shaft and render a correct deposit of the small components more difficult.
In addition, it should be noted that the spatial assignments between component and circuit board may require orientations that deviate from one another by as much as 180.degree.. Thereby, the operator must also grasp the holding handle in a different way, or turn the hand, which can make the activation of a switch in the handle extremely difficult.